考虑到海上浮式风机(floating offshore wind turbine,FOWT)因存在整体晃动导致背景响应强烈,在频域上有时表现为激励频率,且随激励频率的变化而变化,在使用传统调谐质量阻尼器(tuned mass damper,TMD)对其进行振动控制时出现频率失调...考虑到海上浮式风机(floating offshore wind turbine,FOWT)因存在整体晃动导致背景响应强烈,在频域上有时表现为激励频率,且随激励频率的变化而变化,在使用传统调谐质量阻尼器(tuned mass damper,TMD)对其进行振动控制时出现频率失调和效果不佳等现象,该研究设计并提出了一种带碰撞的磁流变弹性体变刚度调谐质量阻尼器(magnetorheological elastomer-pounding tuned mass damper,MRE-PTMD)对FOWT实施半主动控制。在该控制装置中,利用MRE的刚度可调特性,通过半主动控制技术实现阻尼器频率的实时调节,保持对FOWT的最优控制,同时引入限位挡板对MRE材料加以保护并实现碰撞耗能。以驳船型FOWT为例,建立了包含控制装置的17自由度动力方程,对其在风浪联合作用下的减振性能及参数影响进行了研究,并与传统TMD进行了对比。结果表明,所提控制装置能通过对结构响应的实时追踪适时调节阻尼器的控制参数,相比传统TMD有更佳的减振性能和适应性。参数分析表明,增大阻尼器质量比是提升MRE-PTMD工作性能的有效途径,通过对阻尼器质量比及碰撞参数的合理设计可在不过多影响减振效果的情况下实现对MRE的保护及控制装置小型化。展开更多
Magneto-rheological elastomers （MILEs） are used to construct composite structures for micro-vibration control of equipment under stochastic support-motion excitations. The dynamic behavior of MREs as a smart viscoel...Magneto-rheological elastomers （MILEs） are used to construct composite structures for micro-vibration control of equipment under stochastic support-motion excitations. The dynamic behavior of MREs as a smart viscoelastic material is characterized by a complex modulus dependent on vibration frequency and controllable by external magnetic fields. Frequency-domain solution methods for stochastic micro-vibration response analysis of the MRE-based structural systems are developed to derive the system frequency-response function matrices and the expressions of the velocity response spectrum. With these equations, the root-mean-square （RMS） velocity responses in terms of the one-third octave frequency band spectrum can be calculated. Further, the optimization problem of the complex moduli of the MRE cores is defined by minimizing the velocity response spectra and the RMS velocity responses through altering the applied magnetic fields. Simulation results illustrate the influences of MRE parameters on the RMS velocity responses and the high response reduction capacities of the MRE-based structures. In addition, the developed frequency-domain analysis methods are applicable to sandwich beam structures with arbitrary cores characterized by complex shear moduli under stochastic excitations described by power spectral density functions, and are valid for a wide frequency range.展开更多
文摘考虑到海上浮式风机(floating offshore wind turbine,FOWT)因存在整体晃动导致背景响应强烈,在频域上有时表现为激励频率,且随激励频率的变化而变化,在使用传统调谐质量阻尼器(tuned mass damper,TMD)对其进行振动控制时出现频率失调和效果不佳等现象,该研究设计并提出了一种带碰撞的磁流变弹性体变刚度调谐质量阻尼器(magnetorheological elastomer-pounding tuned mass damper,MRE-PTMD)对FOWT实施半主动控制。在该控制装置中,利用MRE的刚度可调特性,通过半主动控制技术实现阻尼器频率的实时调节,保持对FOWT的最优控制,同时引入限位挡板对MRE材料加以保护并实现碰撞耗能。以驳船型FOWT为例,建立了包含控制装置的17自由度动力方程,对其在风浪联合作用下的减振性能及参数影响进行了研究,并与传统TMD进行了对比。结果表明,所提控制装置能通过对结构响应的实时追踪适时调节阻尼器的控制参数,相比传统TMD有更佳的减振性能和适应性。参数分析表明,增大阻尼器质量比是提升MRE-PTMD工作性能的有效途径,通过对阻尼器质量比及碰撞参数的合理设计可在不过多影响减振效果的情况下实现对MRE的保护及控制装置小型化。
基金Research Grants Council of the Hong Kong Special Administrative Region,China Under Grant No.PolyU 5252/07EThe Hong Kong Polytechnic University through the Development of Niche Areas Programme Under Grant No.1-BB95Zhejiang Provincial Natural Science Foundation of China Under Grant No.Y607087)
文摘Magneto-rheological elastomers （MILEs） are used to construct composite structures for micro-vibration control of equipment under stochastic support-motion excitations. The dynamic behavior of MREs as a smart viscoelastic material is characterized by a complex modulus dependent on vibration frequency and controllable by external magnetic fields. Frequency-domain solution methods for stochastic micro-vibration response analysis of the MRE-based structural systems are developed to derive the system frequency-response function matrices and the expressions of the velocity response spectrum. With these equations, the root-mean-square （RMS） velocity responses in terms of the one-third octave frequency band spectrum can be calculated. Further, the optimization problem of the complex moduli of the MRE cores is defined by minimizing the velocity response spectra and the RMS velocity responses through altering the applied magnetic fields. Simulation results illustrate the influences of MRE parameters on the RMS velocity responses and the high response reduction capacities of the MRE-based structures. In addition, the developed frequency-domain analysis methods are applicable to sandwich beam structures with arbitrary cores characterized by complex shear moduli under stochastic excitations described by power spectral density functions, and are valid for a wide frequency range.
